The importance of wearing protective eyewear when one is exposed to sunlight is well-documented. Filtering bright light and protecting the eyes from dangerous ultraviolet (UV) rays, which can lead to short-term and long-term health problems such as cataracts and macular degeneration, or even skin cancer around the eyelids, there is no denying that sunglasses serve an extremely important purpose.
Moreover, for the style-conscious consumer, eyewear is a true fashion accessory, and coordinating one's sunglasses with the color of a particular clothing outfit is quite desirable. Prior to the development of replaceable-lens eyewear, this required procuring multiple pairs of sunglasses.
Replacing lenses in traditional eyewear typically requires a specialty screwdriver, a deft touch, and an investment of time, as the lenses are held in position in the frame by small threaded screws. Various newer devices provide eyeglasses with replaceable-lens capability through means such as a frame with slits or one point for lens coupling. However, such devices do not provide the durability required for extended wear, with a significant risk of the lenses falling out of the frame. Other devices include tedious locking steps and require more than a modicum of time to insert or remove the replaceable lenses from the frame.